Rob Stewart missing

cathal said:
Just curious from whereabouts are you expecting this objective impartial accident analysis to emerge, the Public authorities? That's not going to happen, so who else do you believe will be able to have access to the CCR involved in the incident and can give us an analysis of the particular Unit, its condition on the dive, how it was maintained prior to the dive and also the Diver i.e. their physical health, their qualifications, their prior experience etc. and their final decisions that they took?
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In sequence of expectation:
1) The rebreather manufacturer, see what Poseidon do and release publicly for the standard this can be: http://mkvi.poseidon.com/downloads/Accident_Report_IR-2010-05-31-1.pdf
2) Agencies like NEDU/QinetiQ/Swedish Navy lab etc whose sole purpose is to do Naval R&D inclusive of rebreather function.
See 'what medical examiners need to know about rebreathers' https://www.diversalertnetwork.org/...UHMSProceedings/2014_UHMS_Proceedings_WEB.pdf
3) Public authorities:
https://cognitasresearch.files.word...the-inquest-into-the-death-of-philip-gray.pdf
4) Competent third parties in extremis if none of the above has occurred!
In most cases you do not even need the exact eCCR involved in the incident - just the same model and software version - if the root cause can be identified as a design issue.

The manufacturer is first because if they can't conduct an analysis for why the fatality occurred on their own kit, they are probably unable to do the required unmanned testing of it in the first place, before it is sold = not a good thing for any diver, especially if a trend starts emerging with continued fatalities!
 
Brad, I know this dead horse is something that you continue to beat publicly from time to time, but as far as I am aware, there is little evidence to suggest that any CCR fatalities which have occurred in the past several years have been linked to modern CCR (manufactured in the last 7-8 years) equipment failure or design flaws. Please don't quote the Deep Life database as no one in the worldwide CCR community has any confidence in this database besides you and Alex Deas.
 
Randy Thornton said:
Please don't quote the Deep Life database as no one in the worldwide CCR community has any confidence in this database besides you and Alex Deas.
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None the less, it remains the sole source publicly tracking CCR fatalities; I also understand the download rate and repeat visit rate to it is significant....
Latest version for those looking for recent incidents http://www.deeplife.co.uk/or_files/RB_Fatal_Accident_Database_100725.xls

Randy Thornton said:
as far as I am aware, there is little evidence to suggest that any CCR fatalities which have occurred in the past several years have been linked to modern CCR (manufactured in the last 7-8 years) equipment failure or design flaws.
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Randy, I know. It is just coincidental that some of those same units involved in fatalities when tested/dived have had some interesting design features. To name a few:
Battery bounce
Missing O-rings or spacers allowing CO2 bypass
Lack of retaining/gag strap
Lack of BOV
PPO2 setpoint default of 0.4
Two current limited cells
Miss-assembled (reversible) solenoid
Both opposed flapper valves screwed together onto one side of a DSV
etc etc

The recent Skiles case decided liability, which is fine, he didn't buy it from the manufacturer - case closed.
What I found interesting from a divers perspective is that - quite independently of whoever is diving the eCCR, their drug state, qualifications etc etc - the first ever unmanned lab testing of that unit, for PPO2 control. Revealed that the electronics and cells as dived, were fine BUT that the cells, due to their position and orientation, could be water blocked under certain normal dive conditions. Creating the quirk of either a severe Hypoxic or Hyperoxic condition on the loop (what the diver is breathing) whilst the displays still showed what the cells were reading. Water blocking of the cells.....
If you don't believe it, you can readily test that this can occur, yourself....
It is also separately supported by the fact of multiple public reports, that divers have gotten caustic cocktails on that unit.... A Micropore EAC has to sit in water for quite some time for it to be caustic!
Rotate the EAC/scrubber 90' and the problem goes away & making it look a lot like a HH-CCR!

Looking at this from another perspective, compare the number of fatalities on the Optima to the HH-CCR during the periods when they were using the same electronics/cells:
a) how many fatalites on each
b) what was the difference between the units....
 
Brad,

Again, we're talking about modern CCRs. Much of what you are holding out as design flaws are not found on units manufactured in the last decade.

As far as the Optima goes - I don't have anything to do with the design or the manufacturing of the unit on any level, but to try and point to Wes Skiles' death and claim that he died due to design flaws or unit failure, is simply absurd. Since you were involved with the "expert witness equation for the deceased" you are well aware that the court gave absolutely no credence to the ridiculous postulations of the "expert witness testimony".

Kind regards,
Randy
 
Brad_Horn said:
None the less, it remains the sole source publicly tracking CCR fatalities; I also understand the download rate and repeat visit rate to it is significant....
Latest version for those looking for recent incidents http://www.deeplife.co.uk/or_files/RB_Fatal_Accident_Database_100725.xls
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A donkey fart can seem like a breath of fresh air if you're living in a vacuum.

Being the only example of something may speak volumes about many things but not its veracity.

As to it's popularity, I only need point you to a top ten of any countries music charts to point out the silliness of that as a bolster for your "list". Too many are unaware of the duplicitous nature of it's origins.
 
Brad_Horn said:
In sequence of expectation:
1) The rebreather manufacturer, see what Poseidon do and release publicly for the standard this can be: http://mkvi.poseidon.com/downloads/Accident_Report_IR-2010-05-31-1.pdf
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The manufacturer is an interested party due to their CCR being used when the fatality occurred, therefore any reports from the manufacturer are by definition not objective

Brad_Horn said:
2) Agencies like NEDU/QinetiQ/Swedish Navy lab etc whose sole purpose is to do Naval R&D inclusive of rebreather function.
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These are not Government bodies set up to investigate the cause of fatal diving accidents. The are used as their skill set is a happy by product of their mission and goals.

Brad_Horn said:
See 'what medical examiners need to know about rebreathers' https://www.diversalertnetwork.org/...UHMSProceedings/2014_UHMS_Proceedings_WEB.pdf
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Not relevant to my question and the link did not work for me.

Brad_Horn said:
3) Public authorities:
https://cognitasresearch.files.word...the-inquest-into-the-death-of-philip-gray.pdf
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Exactly, public authorities

Brad_Horn said:
4) Competent third parties in extremis if none of the above has occurred!
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Please elaborate on what you mean by 'competent' and 'third parties' as I've seen and read about 'experts' being shown up quite badly in court proceedings. [/QUOTE]

Brad_Horn said:
In most cases you do not even need the exact eCCR involved in the incident - just the same model and software version - if the root cause can be identified as a design issue.
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Are you kidding me, its the key piece of material and direct evidence for any acident investigation worth the paper its written on.

Brad_Horn said:
The manufacturer is first because if they can't conduct an analysis for why the fatality occurred on their own kit, they are probably unable to do the required unmanned testing of it in the first place, before it is sold = not a good thing for any diver, especially if a trend starts emerging with continued fatalities!
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Nope the manufacturer cannot examine unless they are requested to do so as they are an Interested Party. As per your point 3, Public Authorities are the only body able to issue an impartial and legally binding accident analysis for any fatal diving accident that will be accepted by the relevant Coroner
 
Brad_Horn said:
To name a few:
Battery bounce
Missing O-rings or spacers allowing CO2 bypass
Lack of retaining/gag strap
Lack of BOV
PPO2 setpoint default of 0.4
Two current limited cells
Miss-assembled (reversible) solenoid
Both opposed flapper valves screwed together onto one side of a DSV
etc etc
Click to expand...

I can't agree with you more that there are some major potential failure points on even the most (supposedly) well-designed rebreather.

But I think you're beating around the bush of the big picture here. There is one major shared failure point of every rebreather on the market which no manufacturer yet has the guts to address.

Every single one of them is actually designed to go underwater! Major drowning hazard, right off the bat.

I've actually read every single accident on that database and it seems that every one of those victims was, at one point or another, actually completely underwater as well.

I'd like to see what the so-called experts have to say about that! I've attached a file that illustrates this issue more fully.
 

Attachments

Randy Thornton said:
Again, we're talking about modern CCRs.
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I have to ask what to you defines a modern CCR? Other than integrated Deco, and things like a BOV, not much seems changed over the 40 year old Mk15.5. That unit certainly still sets a standing benchmark for WOB & scrubber duration that puts most units to shame.

Randy Thornton said:
of what you are holding out as design flaws are not found on units manufactured in the last decade.
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Randy, exactly!
Battery bounce - Classic/Vision
Missing O-rings or spacers allowing CO2 bypass - Evo/Inspo amongst other canister units. Just read the last couple of years of BSAC reports if you don't believe this....
Lack of retaining/gag strap - Defender, Evo/Inspo, HH-CCR, Optima, Liberty, SF2, KISS, Meg etc etc noting only the rEvo and Apoc ship with one!
Lack of BOV - SF2, Liberty (now fixed with a EN250 rated one), rEvo
PPO2 setpoint default of 0.4 - JJ-CCR (now fixed with a software upgrade) Note: not an issue on the HH-CCR, so likely the vibrating HUD may have offset this.....
Two current limited cells - all current recreational eCCRs using voting logic, NOT Poseidon
Miss-assembled (reversible) solenoid - Meg, Based on the NEDU investigation of one.
Both opposed flapper valves screwed together onto one side of a DSV - Hollis Prism2
etc etc

resolve those and then we can start debating the finer points of CCR design. Like divers actually knowing the WOB and actual scrubber duration of the units they are diving!

Randy Thornton said:
to try and point to Wes Skiles' death and claim that he died due to design flaws or unit failure, is simply absurd.
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Randy AFAIK, no failure of anything on the unit in question was ever identified! The cells, electronics and rebreather loop itself all performed exactly as designed to do. The DSV even fell out of the divers mouth when they went unconscious - allowing drowning - exactly as it was designed to do.....

Randy Thornton said:
you were involved with the "expert witness equation for the deceased" you are well aware that the court gave absolutely no credence to the ridiculous postulations of the "expert witness testimony".
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Again Randy, the court case was looking for liability. And liability alone.
Done properly and professionally, an accident analysis will not look for nor identity liability; just the root cause of the fatality. In this example it didn't matter who was diving the unit, nor if they owned it, nor the number cert cards they had collected! As one of the defence's expert divers found out very shortly after that fatal dive when he had a Hyperoxic incident recreating the dive.....
 
oya said:
But I think you're beating around the bush of the big picture here. There is one major shared failure point of every rebreather on the market which no manufacturer yet has the guts to address.
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I have to support rEvo on this, as your not quite right. They have gone against the trend and fitted every rebreather they ship with a good quality Drager gag/retaining strap. Something that stops a diver drowning.... due to being underwater.

As they mandate its use, for very good reason http://militarymedicine.amsus.org/doi/pdf/10.7205/MILMED-D-10-00420 it will be interesting to see what the consequences are for any of their authorised instructors who do not use it and/or remove it from students/customers units...

For those rebreather manufacturers struggling to get CE certification, its also a near freebie that ticks one of the requirements off for their technical file.
 
cathal said:
The manufacturer is an interested party due to their CCR being used when the fatality occurred, therefore any reports from the manufacturer are by definition not objective.
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cathal said:
you kidding me, its the key piece of material and direct evidence for any acident investigation worth the paper its written on.
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cathal said:
the manufacturer cannot examine unless they are requested to do so as they are an Interested Party.
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I think you are crossing some wires over any post-incident tear down and inspection of the rebreather(s) involved in a fatality with actual accident analysis.

Nothing stopped one of the two manufacturers doing a good job and providing objective reporting in this case:
http://www.theargus.co.uk/news/1184...ch_set_out_from_Brighton_Marina___went_wrong/
https://www.divingincidents.org/reports/304

A tear down will tell you exactly what unit was used and software it had, date and batch # of cells and mV, make of batteries, quantity and type of sorb and any modification to the unit from standard etc etc. Once you have this information, anyone inclusive of the manufacturer, can conduct accident analysis in order to recreate the incident and identify the root cause. If indeed one can be found for that incident.
A tear down will also tell you if there was no scrubber fitted, an O-ring has been left out or if 2 cells were current limited etc etc It will tell you if the unit was modified like Dave Shaw's Mk15.5. It will tell you if it is stock standard with no modifications, has perfectly good cells and batteries and working electronics.
It will not tell you that the unit can have a hypoxic/hyperoxic loop under certain conditions whilst still displaying the setpoint or if the WOB is too high for the divers workload or if the scrubber is incapable of supporting 3 dives to 70m (noting water temp, diluent and divers probable workload)! Without unmanned testing and accident analysis of a rebreather after an unexplained fatality or series of fatalities on one, you are just assuming it works.

cathal said:
Please elaborate on what you mean by 'competent' and 'third parties' as I've seen and read about 'experts' being shown up quite badly in court proceedings.
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The Barrett case has probably the best detail that I am aware of what experts have said about a rebreathers design and function, based on accident analysis; with some quite interesting technical information about the units design revealed by both sides experts as a result:
http://crossbowdiving.com/barrett
 
I thought we were over with this after their sorry excuse for an expert witness lost them the Skiles case (and rightfully so) I hope this resurfacing is not you prepping for a new frivolous law suit. I can only hope that any new clients you have saw Alex's plastic bag camera housing video trying to prove a design flaw and now know not to waste their time or money.
 
Brad_Horn said:
I have to support rEvo on this, as your not quite right. They have gone against the trend and fitted every rebreather they ship with a good quality Drager gag/retaining strap. Something that stops a diver drowning.... due to being underwater.
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Only this passed weekend, a diver got in trouble in the UK and had to be airlifted to hospital (no idea on which CCR) and it appears that he was using a retaining strap - and that saved his life and he is on the mend (thankfully). First time I've heard of one actually resulting in saving someone.
 
Brad the default setpoint on the jj-ccr has never been 0.4 its always been 0.7 and 1.2/1.3 there may have been the ability to set 0.4 but it has never been recommend/condoned/taught by shearwater/jj factory and any of the training programs
 
I'm at a loss to understand why having a setpoint of 0.4 is a design flaw. Many units have a 0.5 or 0.7 setpoint setting, both of which are also rarely if ever used in the water, why is 0.4 so awful and 0.5 "ok"? My original Meg had a 0.4 setting which I didn't really use even on land. I think I may have prebreathed using it once or twice - somehow surviving.
 
rjack said:
I'm at a loss to understand why having a setpoint of 0.4 is a design flaw. Many units have a 0.5 or 0.7 setpoint setting, both of which are also rarely if ever used in the water, why is 0.4 so awful and 0.5 "ok"? My original Meg had a 0.4 setting which I didn't really use even on land. I think I may have prebreathed using it once or twice - somehow surviving.
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I will tell you one reason it is ESSENTIAL (for some divers at least) to have the option of a lower setpoint.... because I regularly dive (and TEACH!) at high enough altitudes that a .7 is very difficult, if not impossible to maintain at the surface.
 
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